Abstract: The invention is directed to methods for direct patterning of silicon. The invention provides the ability to fabricate complex surfaces in silicon with three dimensional features of high resolution and complex detail. The invention is suitable, for example, for use in soft lithography as embodiments of the invention can quickly create a master for use in soft lithography. In an embodiment of the invention, electrochemical etching of silicon, such as a silicon wafer, for example, is conducted while at least a portion of the silicon surface is exposed to an optical pattern. The etching creates porous silicon in the substrate, and removal of the porous silicon layer leaves a three-dimensional structure correlating to the optical pattern.

Abstract: The invention includes sensors and sensing methods for determining cell morphology and/or chemical composition of an analyte. A porous substrate exhibiting a first optical signal is exposed to a target analyte and subsequently monitored for changes in the optical signal. More specifically, a photonic or porous substrate having a well-defined and highly tunable reflectivity or transmission spectrum, such as porous silicon (Si), porous alumina, porous Ge, porous GaAs, porous SiO2 and porous polymer, is used for example. A porous or photonic substrate is exposed to an analyte, such as a cell or other macromolecule, and changes in the scattered light are observed over time to determine cell morphology and/or chemical composition of the analyte using the substrate.

Abstract: A system and method for free space, optical remote sensing of a potential threat agent using spectrally responsive sensor material. In one example the sensor material is formed by particles, which in one particular form are porous photonic crystals. The particles are dispersed into an area being monitored for the presence of the potential threat agent. A pair of lasers is used to generate optical light beams that are directed at the sensor particles after the particles have been dispersed. The light reflected by the sensor particles is then analyzed. The presence of the potential threat agent causes a shift in the spectral peak of light reflected from the sensor particles that can be sensed using photo detectors and a processing subsystem. The system can be tuned to remotely detect for specific chemical, biological or environmental agents that may be present within a given area.

Abstract: A method for forming photonic particles, where the method includes the steps of preparing a porous photonic material layer, patterning a soluble polymer on the porous photonic material layer, leaving dividing portions of the material layer untreated, infusing the polymer into the material layer, and removing the dividing portions of the material to obtain the photonic particles.

Abstract: The invention is related to optical particles (10), use of optical particles in sensing applications, and methods of fabricating optical particles that can target a desired analyte. The invention is also related to the self assembly of individual optical particles. An advantage of the invention is that it includes self-assembling individual photonic crystal sensors onto a target. In an embodiment of the invention, a processed sensor structure having two generally opposing surfaces is provided, wherein each of the opposing surfaces have different surface affinities, with a first optical structure formed on one of the opposing surfaces, and a second optical structure formed on the other of the opposing surfaces. The chemically and optically asymmetric opposing surfaces will spontaneously align at an organic liquid/water interface. Changes in the optical response of at least one of the opposing surfaces indicate the presence of a particular analyte for sensing applications.

Abstract: A nanoporous silicon support comprising a plurality of macropores is provided to function as a bioreactor for the maintenance of cells in culture in a differentiated state. Each cell or group of cells is grown in an individual macropore and is provided with nutrients by means such as perfusion of the nanoporous silicon support with fluid. The macropores may be between 0.2 and 200 microns and be coated with a substance that promotes cell adhesion. The support containing cells may be used to used to test compounds for biological activity, metabolism, toxicity, mutagenicity, carcinogenicity or to characterize novel or unknown comounds. The supports are sufficiently robust that they may be assembled into larger reactors to simulate organ function or be used for the production of biomolecules.

Abstract: A method for analyzing gaseous or liquid samples is provided. Samples are interacted with pores of a porous thin film. A time-varying response of reflectivity is obtained from the surface of the porous thin film during the interaction. One or more analytes forming the sample or a part of the sample are identified based upon the time-varying response.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: An initiator explosive for detonating a second explosive that includes nanocrystalline silicon containing a plurality of pores and a solid state oxidant disposed within said pores.

Abstract: The invention is a nanoporous silicon bioreactor for the maintenance of cells in culture in a differentiated state. Each cell or group of cells is grown in an individual macropore and is provided with nutrients by perfusion of the nanoporous silicon support with fluid. Bioreactors may be used to used to test compounds for biological activity, metabolism, toxicity, mutagenicity, carcinogenicity or to characterize novel or unknown comounds. Additionally, the bioreactors are sufficiently robust that they may be assembled into larger reactors to simulate organ function or be used for the production of biomolecules.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: A nanoporous silicon support comprising a plurality of macropores is provided to function as a bioreactor for the maintenance of cells in culture in a differentiated state. Each cell or group of cells is grown in an individual macropore and is provided with nutrients such as by perfusion of the nanoporous silicon support with fluid. The macropores may be between 0.2 and 200 microns and be coated with a substance that provides cell adhesion. The support containing cells may be used to used to test compounds for biological activity, metabolism, toxicity, mutagenicity, carcinogenicity or to characterize novel or unknown comounds. The support is sufficiently robust that it may be assembled into larger reactors to simulate organ function or be used for the production of biomolecules.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: A method for analyzing gaseous or liquid samples is provided. Samples are interacted with pores of a porous thin film. A time-varying response of reflectivity is obtained from the surface of the porous thin film during the interaction. One or more analytes forming the sample or a part of the sample are identified based upon the time-varying response.

Abstract: The invention is a nanoporous silicon bioreactor for the maintenance of cells in culture in a differentiated state. Each cell or group of cells is grown in an individual macropore and is provided with nutrients by perfusion of the nanoporous silicon support with fluid. Bioreactors may be used to used to test compounds for biological activity, metabolism, toxicity, mutagenicity, carcinogenicity or to characterize novel or unknown comounds. Additionally, the bioreactors are sufficiently robust that they may be assembled into larger reactors to simulate organ function or be used for the production of biomolecules.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Abstract: An n-type silicon (Si) wafer is galvanostatically etched in a hydrofluoric acid (HF)-containing solution while being illuminated with a 300 watt tungsten light source to form porous silicon with luminescent properties. Photoluminescence of the porous silicon is monitored using a short wavelength visible or ultraviolet light source and a monochromator/CCD detector assembly. Upon exposure to organic solvents, the photoluminescence is quenched. Within seconds of removal of the solvent, the original intensity is recovered and further exposure of the porous silicon to organic solvents will again result in quenching of the luminescence.

Abstract: An n-type silicon (Si) wafer is galvanostatically etched in a hydrofluoric acid (HF)-containing solution while being illuminated with a 300 watt tungsten light source to form porous silicon with luminescent properties. Photoluminescence of the porous silicon is monitored using a short wavelength visible or ultraviolet light source and a monochromator/CCD detector assembly. Upon exposure to organic solvents, the photoluminescence is quenched. Within seconds of removal of the solvent, the original intensity is recovered and further exposure of the porous silicon to organic solvents will again result in quenching of the luminescence.

Abstract: A polished wafer of single-crystal silicon (Si) is ohmically contacted on its backside to a copper wire to provide a working electrode. The wafer and a counterelectrode are immersed in a solution of aqueous HF and ethanol within an optical quality cuvette. Lithographic images are projected onto the silicon wafer within the solution, and the wafer is etched galvanostatically at a low current density until a predetermined charge density is attained. The areas of an n-type silicon wafer exposed to the light during the etch will exhibit visible luminescence when the wafer is illuminated with an ultraviolet (UV) lamp or other short wavelength visible light. The areas of the wafer that were not exposed to the pattern during etch will not luminesce.